The ITU-T G.709 recommendation entitled, “Interface for the optical transport network (OTN)” (hereinafter “G.709”) is an international standard for optical networks and is intended to converge existing packet services, such as ATM, IP Ethernet, and TDM broadband services as well as SONET and SDH. A network terminal compliant with G.709 transports data frames or Optical Transport Units (OTUs) at a fixed frame length and with a fixed rate of, for example, of 10.7 Gigabits/second (“Gbit/s”). Since each frame includes forward error correction (FEC) bits and overhead bits, the effective payload data rate of a 10.7 Gbit/s G.709 OTU2 payload is approximately 10 Gbit/s.
Wavelength division multiplexed (WDM) systems compliant with G.709 are known. In such systems, a plurality of optical channels, each at a different wavelength, carry the data frames. WDM systems or spans typically include a transmit terminal, where the optical channels are combined onto an optical communication path, and a receive terminal, where the optical channels are demultiplexed and supplied to corresponding receivers. Typically, one or more optical amplifier components may be provided between transmit and receive terminals in order to offset losses associated with the optical communication path. Various components within a WDM system may degrade over time. As a result, over the life of a WDM system, performance may degrade such that the system does not communicate error free or may not communicate at all.